Feeding mechanism for grinding machines



June 10, 1930.

G. H. SMITH FEEDING MECHANISM FOR GRINDING MACHINES Filed July 26, 1928 2 Sheets-Sheet l SIM/vent GEO GE H. SMITH Wwmzssss I June 10, 1930. s. H. SMITH FEEDING MECHANISM FOR GRINDING MACHINES 2 Sheets-Sheet 2 Filed July 26, 1928 GEORGE H. SMITH WITNESSES ,abbonuq Patented June 10, 1930 TNT @FIQE GEORGE H. SMITH, OF WORCESTER, MASSACHUSETTS, ASSIGNOB TO NORTON COMPANY,

OF WORCESTER, MASSACHUSETTS, A CORPORATION OF MASSACHUSETTS FEEDING MECHANISM IEQR GRINDING MACHINES Application filed July 28, 1928. SeriallNo. 295,397.

This invention relates to grinding ma-i chines and moreparticularly to a feeding mechanism for controlling themovement of the grindingwheel toward and from the work being ground.

In the ordinary grinding machine-for grinding cylindrical objects, such as crankpins andthe like, a feeding mechanism is employed to control the movement of the grinding wheel. This mechanism usually comprises a nut and screw mechanism which is operatively connected to the wheel slide, and manually controlled micrometer mechanism is arranged to rotate the screw to produce the desired'feeding. action. .These feed.

mechanisms are in some instances supplemented with a power drive which is arranged to rotate the screw by power to produce an infeed of the grinding wheel. A stop is arranged to cooperate with an abutment on the micrometer mechanism to definitely stop the infeed of the wheel at a predetermined point. a

In the production grinding of crankshafts and the like with the standard type of wheel feed mechanism, it is necessary, after a crankpin has been finished, to move the grinding wheel rearwardly through a considerable distance because of the offset relation of the crankpins, in order that the work'table may the feed wheel to remove the grinding wheel a suflicient distance from the work to permit table traverse. ator keep a mental count of the number of turns of the manual feed wheel at each infeed of the grinding wheel and to turn the feed wheel in a reverse direction through the same number of turns to insure that the grinding wheel is removed a sufficient distance to clear the adj acent projecting portions of the crankshaft. feed wheel to cause a rearward movement of the grinding wheel and to continue this movement until by observation the grinding wheel has moved rearwardly a sufiicientvdis? tance to clear the projecting portions of the It is necessary that the oper- The operator may if desired turn the crankshaft; Both of these methods are slowv and require considerable attention and'skill upon the part .of the operator. Afterxthe table has been traversed, to position the next pin, the operator then rotates the feed mechmechanism for feeding the grinding wheel throughout the major portion of its travel but which is arranged to permit the operator to feed the wheel manually into the work during the grinding operation. Such a mechanism has, however, lacked a timing device which so coordinates the power and manual feeding. mechanisms that the stop which limits the power infeed of the "wheel disengages the power feed at a predetermined position of the wheel slide regardless of the amount of manual and power feed'on the previous grinding operation.

It is one object of this invention to overcomethis difficulty and to provide a feeding mechanism'which may be operated by power to bring the wheel rapidly towards the work and then by hand to obtain the desired slow feeding during the grinding'operation, and which is so arranged that the power feed alone may be used for removing the Wheel from the work, without requiring any readjustment of the relationship between the power and manual feeding mechanisms. This may be accomplished by providing an indexing mechanism which is rotated in timed relation with the feed screw regardless of whether the feed'screw is turnedby hand or by power, so that the necessity of manually controlling the relationship between the manual and power feed mechanismoas heretofore required is eliminated. The indexing mech-' disconnection of the power feed when the wheel slide reaches a predetermined position in either direction. This may be accomplished by providing adjustable stop members on the indexing mechanism, which is geared to rotate in timed relation with the feed screw, and so arranging the mechanism that these stopping members will positively and automatically disconnect the power feed when the wheel slide has reached a predetermined position in either direction.

It is a still further object of this invention to provide a power feeding mechanism which is so arranged that the operator holds a control lever in one of two positions to produce either a forward or a rearward feed of the grinding wheel, and when the operator releases his grasp upon the lever, the lever is moved automatically into a neutral position, thereby stopping the power feed. This mechanism may comprise a yieldable device including a pair of opposed springs arranged to throw the power clutch into neutral when the operator releases his grasp upon the control lever.

It is another object of this invention to provide an interlocked relation between the manual and the power feed mechanisms so that when the power feed is operating, the manual feed wheel is stationary, and when the manual feed is in engagement to rotate the feed screw, the power feed is disengaged. This may be accomplished by an interlocked operation of the clutch mechanism, which controls the connection of the power to operate the feed screw, and a second clutch which controls the manual feeding of the wheel. These two clutches are so arranged and connected that when one is operatively connected to rotate the feed screw, the other is disconnected.

One embodiment of this invention has been illustrated in the drawings, in which like reference numerals indicate like parts:

Fig. 1 is a front elevation of the feed mechanism removed from the machine base;

Fig. 2 is a top plan view showing parts of the mechanism in section, taken approximately on the line 22 of Fig. 1;

Fig. 3 is a diagrammatic view illustrating the gearing in the mechanism showing the connection between the feed screw and the index plate;

Fig. 4: is a fragmentary sectional view taken approximately on the line 47 of Fig.

Fig. 5 1s a fragmentary sectional view taken approximately on the line 5-5 of Fig.

Fig. 6 is a fragmentary sectional view taken approximately on the line 66 of Fig. 1; and

Fig. 7 is a fragmentary perspective view of the mechanism for disengaging the clutch controlling the manual feed.

This invention comprises a grinding wheel feeding mechanism for grinding machines having a power mechanism for moving the grinding wheel at a rapid rate to remove the grinding wheel from engagement with the when the work has been reduced to a preu determined size, the operator may, by movement of asingle lever, effect a rapid removal of the grinding wheel from operative engagement with the work to an inoperative position.

As illustrated in the drawings, one embodiment of the invention has been snown which is constructed and arranged as a unitary mechanism so that it may be inserted as a unit into machines already in use in the grinding field. The mechanism comprises a frame which is bolted by screws 13 to the front base of the machine. A wheel slide as indicated by a projection of a nut 15 has a threaded portion adapted to engage a feed screw 16 to control the feeding movement of the cutting tool toward and from the work.

The feed screw mechanism is so constructed and arranged that it may be operated either by hand or by power to control the feeding movement of the grinding wheel. In the production grinding of crankshafts and the like, it has been found advantageous to provide a rapid feeding movement of the grinding wheel to move the grinding wheel rapidly into position adjacent the surface of the work before grinding and after the work has been ground to permit a rapid removal of the grinding wheel from operative engagement with the work so that the table may be traversed to bring the next pin on the crankshaft into alignment with the grinding wheel. The feeding movement during the grinding operation is taken care of by means of a hand feed wheel so that the operator has manual control of the grinding feed on the wheel and may feed the wheel through the desired distance until the grinding gauge reads the re quired size, whereupon the mechanism may be thrown into reverse to remove the wheel rapidly from the work.

The feed screw 16 is provided with a gear 17 meshing with an intermediate gear 18 which is supported on the end of a shaft 1.9 journalled in suitable bearings in the frame 12. A bevel gear 21 is mounted on the other end of the shaft 19 and in turn meshes with the bevel gears 22 and 23 which are rotatably mounted on the shaft 24. A pulley 26 is mounted on the outer end of the shaft 24: and

is arrangedto be driven by a belt or other power connections from any suit-able source of power, preferably from a power shaft within the base of the machine. The gears 22 and 23 are preferably loosely mounted on the shaft 24 and are arranged so that either may be locked to the shaft 24 to transmit power to the gear 21 and from there through gears 18 and 17 to rotate the feed screw in the desired direction.

As illustrated in the drawings a cone clutch member 27 is slidably keyed to the shaft 24 by a key 28. The member 27 may be of any of the well known friction clutches but for simplicity of illustration a double cone clutch type has been illustrated which has a pair of frusto-conically shaped surfaces. 29 and 30 adapted to engage correspondingly shaped apertures 31 and 32 within the gears 22 and 23 respectively. It will be. readily apparent from this construction that the operator may engage theclutch to lock either the gear 22 or the gear 23 to transmit power to rotate the feed screw 16 in the desired direction.

- Any suitable operating mechanism may be employed to shift the clutch member 27 to produce the desired feeding action. As illustrated in the drawings the clutch mem ber 27 is provided with an annular groove 33 adapted to be engaged bycthe pins 34 and 35 of the yoked member 36 which is pivotally mounted on a stud 37 in the frame 12. By swinging theyoked member 36 the clutch 27 may be engaged with the aperture 31or the aperture 32 to lockt-he respective gears 22 or 23 so that they rotate with the shaft 24. A hand .lever 39 is pivotally mounted on a stud 40 mounted on a bracket 41 which is bolted to the frame 12. The lever 39 is provided with a pin 42 adapted to engage an annular roove 43 in a spool-shaped member-44 which is in turn mounted onthe outer end of a rod 45. The rod 45 isslidably mounted in bearings 46 and 47 in the frame 12. The other end of the rod 45 is provided with a similar spool-shaped member 48 having an annular groove 49 which engages a pin 50 on the lever 51. The lever 51 is pivotally mounted on a stud 52 on the front of the frame 12. The pin 50 passes .through a boss 53 on the lever 52 and has a projecting portion 54 which engages a vertically extending groove 55 in the projection 56 of the yoked member 36.

It will be readily apparent from this construction that when thelever 39 is moved toward the right, asis viewed in Fig. 1, it will transmit a corresponding movement to the rod 45, the pivotally mounted arm 51 and the yoked member 36 to slide the clutch member 27 into engagement with the bevel'gear 23 which operates to rotate the feed screwand cause arearward movement .of the nut 15 and consequently the wheel slide and grinding wheel. corresponding movement of the lever 39 in the direction toward the left, as viewed in Fig. 1, operates to move the rod 45, lever 51, yoked member 36 and clutch member 27 in the opposite direction to lock the gear 22 to the shaft 24 and thereby rotate the feed screw 16 in the opposite direction to produce a forward .or infeed of the grinding wheel.

In order that the clutch member 27 may be normally held in a neutral position and also that it may be returned to this position when the operator releases his grasp upon the lever 39, a mechanism is provided which will automatically return the clutch to the required position. The spring 59 is loosely mounted on the shaft 45 and is interposed between the flange 57- on the rod 45 and the surface 61 on the bearing member 47. The spring is also loosely mounted on the rod 45 and is interposed between the flange 58 and the face 62 on the bearing 47. 7

It will thus be seen from this construction that as the lever 39 is moved in one or the other direction either the spring 59 or the spring 60 is compressed. Theoperator holds the lever 39 in the desired position to permit the grinding wheel slide to move the desired distance toward or from the work. If at any time during this travel, theoperator releases his grasp on the lever 39 the released tension of the spring 59 or 60 depending upon which spring is compressed operates to move the rod 45 and consequently slide the clutch member 27 into itsneutral position. It will be readily apparent that it is not necessary for the operator to manually move the lever into a neutral position to stop the feeding movement since it is merely necessary for him to release his grasp on the lever 39'when desired.

A primary feature of this invention is to provide a'feed mechanism capable of giving rapid movement of the grinding wheel slide toward and from its grinding position, which is so arranged that the rapid power feed of the wheel is disengaged just before the grinding wheel contacts with the surface of the work to be ground. For this purpose a simplified stopping mechanism is provided which is operatively connected to rotate in timed relation with the feed screw regardless V of whether the feed screw is rotated by power or by hand.

To accomplish this result, a wormis mounted in a bearing 66 in the frame 12 at one end and having its other end rigidly mounted in a hub 67 extending from the gear 23. The worm shaft 65 is mounted in fixed relation with the hub 67 so that it rotates as the gear 23 is moved. The shaft24 is loosely mounted in the gear 23 which in turn is rotatably supported in a bearing 68 in the frame 12. It'will thus be seen that any rotation of the feed screw 16 will be transmitted back through the gear '18, bevel gear 21, and bevel gear 23 to cause a corresponding rotation of the worm 65. The worm meshes with a worm gear 69 which is supported on the outer end of a shaft 70. The other end of the shaft 70 is provided with a gear 71 which in turn meshes with a gear 72. The gear 72 is held in fixed relation with the gear 73 by means of screws 74 which lock the two gears. These gears are rotatably mounted on a stud 7 5 which is also supported in frame 12. It will be readily apparent that any rotation of the feed screw 16 in either direction is transmitted through the gear mechanism to rotate the gear 73 in a corresponding direction.

In order that the gear 73 may be arranged to disconnect the power clutch 27 when the wheel slide reaches the desired position, a stopping mechanism is so arranged that it will automatically move the clutch member 27 in the desired direction at the proper time. To this end, a stop pin 7 6 is mounted in the periphery of the disk-shaped member 77 which is rotatably supported on a hub 78 on the gear 73. To permit adjustment of the stop pin 76, a plurality of openings 79 may be provided within the hub 78 which are adapted to be engaged by a spring pressed plunger 80 in the member 77.

From this construction, it is readily seen that the operator may, by manipulating the spring pressed plunger 80 withdraw it from engagement with the hole- 79 and swing the member to the required position until the spring pressed plunger 80 drops into the proper hole 79 in the hub. The stopping pin 76 is provided to limit the rearward movement of the wheel slide and inasmuch as the rearward movement does not require a precision adjustment to stop the feed within fine limits, this form of adjustment for the stopping member is suflicient. The pin 76 is arranged so that when it is rotated with the gear 73, it will contact with a projection 81 on a swinging lever 82 which is pivotally mounted on a stud 83 on the front of the frame 12. The lever 82 is provided with a pair of lugs 84 and 85 which engage the opposite sides of an annular groove 86 on the rod 45. As the stop pin 76 rotates in a counterclockwise direction as viewed in Fig. 1 the stop pin will strike the projection 81 and swing the lever 82.

If the operator holds the lever 39 in a position toward the right as viewed in Fig. 1 so that the feed screw is rotating to remove the grinding Wheel from operative engagement with the piece of work, then the stop pin 76 will eventually contact with the projection 81 of the lever 82 and then continued movementof the stop 76 operates to swing the lever 82 which in turn operates through the rod 45, the lever 51, and yoked member 36 to slide the clutch member into a neutral position. The machine is then in position to traverse the work supporting table to position the next bearing or pin on the crankshaft in alignment with the grinding wheel.

When the work is positioned so that the next pin or hearing on the crankshaft is in alignment with the grinding wheel, the operator swings the lever 39 toward the left as viewed in Fig. 1 whereupon a feeding movement is transmitted through the gear mechanism to rotate the feed screw 16 in the required direction to produce an infeed of the grinding wheel. The rapid infeed of the wheel continues until the abutment 90 contacts with the projection 91 011 the lever 82. This movement swings the lever 82, the rod 15, lever 51 and yoked member 36 toward the right as viewed in Figs. 1 and 2 to disengage the clutch members before the grinding wheel contacts with the surface of the work.

In order that the grinding wheel may be moved rapidly up to a position close to work of any size, the abutment 90 is provided with a suitable micrometer adjustment whereby the position may be varied according to the size of the work being ground and also to adjust for wheel wear. The abutment 90 is mounted on the outer end of a member 93 which is rotatably supported on a hub 94 of the gear 73. The member 93 is held in position by a washer 95 and nut 96 threaded on the outer end of the stud 75. The outer end of the member 93 is connected to the gear 73 by means of a pinion 97 which is slidably mounted in an aperture 98 within, the member 93. The pinion 97 is held in mesh with the gear 73 by means of a spring 99 which surrounds a reduced portion 100 of the pinion 93 and is interposed between the end of the pinion and a portion of the lever 93. To permit adjustment of the abutment 90 relative to the gear 73, the pinion 97 having a reduced portion 100 is connected to the index plate 102 which is provided with a projecting pin 103 adapted to engage any one of a plurality of holes 104 in the member 93.

It will be readily apparent from this construction that when the operator desires to make an adjustment to vary the throw-oft point of the power mechanism on the infeed, he grasps the'knob on the index plate 102, pulls it outwardly to disengage the pin 103 from the hole 104 and while then disengaged rotates the index plate the necessary amount to make the required adjustment, then permits the pin 103 to slip into another hole in the member 93. By this adjustment the operator swings the member 93 relative to the gear 73 thereby changing the time at which the abutment 90 will engage the projection 91 on the lever 82. The index plate 102 may be provided with suitable graduations on its periphery so that the operator may, by reading the graduations, make a fine adjustment of the stopping mechanism so that the mounted on a shaft108.

rapid feeding movement 7 of the grinding wheel may be continued until the grinding wheel is about to contact with the surface of the work.

In order that the grinding wheel may be fed manually to produce the desired grind; ing action, amanually operable feed wheel 105 is .provided to produce the required adjustment of the wheel. The hand Wheel may be connected directly to rotate the feed screw in which case the hand wheel 105 will be rotated when the feeding is taking place by power. It is desirable, however, to eliminate the rotation of the hand feed wheel 105 when the feed screw is rotated by power, thereby eliminating the danger of the operator being caught in the rapidly rotating wheel and being injured thereby. To avoid this difficulty, a mechanism is so arranged as to permit the manual rotation of the feed screw only when the power mechanism is disconnected. This mechanism comprises a gear 106 which meshes with a gear 118 and is keyed to a sleeve 107 which is rotatably the sleeve 107 is provided with a cone clutch member 109 having a frusto-conical surface adapted to engage a correspondingly shaped clutch member 110 which is in turn keyed to a sleeve 111. The sleeve 111 is rotatably mounted in a bushing 112 in the frame 12. The hand wheel 105 is mounted on the outer end of the'sleeve 112 and is keyed thereto by a key 113 so that any rotation of the hand wheel operates through the sleeve 111, clutch members 110 and 109 and gear mechanism including gears 106, 18, 17 to rotate the feed screw 16 in the desired direction.

To prevent rotation of the hand wheel 105 when it is desired to rotate the feed screw by power, it is preferable to tie up the clutch mechanism, the cone clutch 109 and 110, with the manually operable lever 39 so that When the lever ismoved to engage the power clutch, the clutch controlling the manual feed will be disengaged. As illustrated in the drawings, a collar 115 surrounds the sleeve 111 and is positioned between the outer face of the bushing 112 and the hub 116 on the handwheel 105. The collar 15 is provided with a plurality of V-shaped grooves 118 which engage a corresponding number of pins 117 projecting from the outer facing of the bushing 112. It will be readily apparent from this construction that if the collar 115 is rotated, the

V-shaped grooves ride up the pins 118 and move the sleeve 111, hand wheel 105 and consequently the clutch member 110 in an outward direction, thereby disengaging the member 110 from the member 109 so that the clutch member 109 is free to rotate without transmitting its rotation tothe member 110 and to the hand wheel 105. In order that movement of the collar 115 may be operated to engage and disengage theclutch member The front end of 110 at the desired time, a link 120 is provided which is connected to the lever 39 by means of a stud 121 so that any movement of the lever will be transmitted to give a correspond ing movement of the link 120. The other end of the link 120 is connected by means of a pin 122 to the collar 115 so that the movement of the'lever 39 is transmitted to'cause a rotary movement to the collar 115. In order that the clutch member 110 may be maintained in frictional engagement with the clutch member 109, a spring 123 is interposed between a portion 124 of the sleeve 111 and a bushing 125 which surrounds the shaft 108 and is held in position by a head or enlarged portion 126 on its outer end. The tension of the spring 123 is exerted to force the member 110 in an inward direction as permitted by the position of the'collar 115.

It will be readily apparent fromthis disclosure that when the operator moves the lever 39 toward the left, as viewed in Figs. 1 and 2, this movement of the lever 39 acts to engage the clutch member 27 to cause an inward feeding movement of the grinding wheel and simultaneously acts to rotate the collar 115 to disengage the clutch members 110 and 109 and thereby prevent manual feeding of the grinding Wheel during the period in which the power remains engaged. The forward feeding movement of the grinding wheel continues until the abutment contacts with the projection 91 on the lever 82 and swings the lever and mechanism connected therewith to disengage the clutch 27 and thereby stop the power infeed before the grinding wheel contacts with the surface of the work. Simultaneously with the swinging of the lever 82 to disengage the clutch 27, the rod 45'which is connected with the lever 39 swings the lever 39 toward the right and thereby rotates the collar 115 and permits.

the V-shaped groove 118 to ride down the pin 117 and engage the clutch member 110 with the clutch member 109 to permit the operator to feed the wheel manually during the grinding operation. I 1

The abutment 90 on the member 93 is so shaped that during the forward feeding movement the cylindrical surface 130 passes under the corner of the projection 91 so that it is impossible for the operator to move the lever 39 toward the left and cause a further infeed of the grinding wheel by power, but the operator must continue the manual feed This, however, does not prevent the operator.

from moving the lever 39 toward the right, as viewed in Fig. 1, after the work has been reduced to the desired size and thereby remove the grinding wheel rapidly from its operative engagement with the surface of the work. As previously described, the. rearward movement of the grinding Wheel continues until the stop 76 which is new rotating a counterclockwis ,d rection strikes the projection 81 and swings the lever and the connected mechanism toward the left to disengage the power clutch. This cycle of operation may be continued. It is readily apparent from the foregoing disclosure that the operator may manually feed the grinding wheel to any desired extent or may, by movement of the manually operable control lever 39 throw in the power feed, and so adjust the stopping mechanism that the power feed may be disengaged at any desired position of the wheel slide as it moves in either direction.

Having thus described the invention, what is claimed as new and is desired to secure by Letters Patent is:

1. A feeding mechanism for a grinding machine wheel slide comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, a power mechanism to rotate the feed screw and feed the wheel continuously towards the work and automatic means to positively disconnect the power mechanism when the slide has reached any predetermined position.

2. A feeding mechanism for a grinding machine wheel slide comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, a power mechanism to rotate the feed screw and feed the wheel continuously towards the work, and automatic means which moves always in timed relation with the feed screw and serves to positively disconnect the power mechanism when the slide has reached any predetermined position.

3. A feeding mechanism for 'a grinding machine wheel slide comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, a power mechanism, manual means to connect said mechanism to rotate the feed screw continuously and automatic means to positively disconnect the power mechanism when the slide has reached a predetermined position in its travel in either direction.

4. A feed mechanism for a grinding machine wheel slide comprising a feed screw,

a nut engaging said screwand operatively connected to the wheel slide, mechanism in cluding a clutch to rotate said feed screw, an index plate, meansto rotate said plate in timed relation with the feed screw and means including an adjustable stop on said plate arranged to positively disconnect said clutch when the wheel slide has reached a predetermined position.

5. A feed mechanism for a grinding machine wheel slide comprising a feed screw,

a nut engaging said screw and operatively connected to the wheel slide, mechanism including a clutch to rotate the feed screw, an index plate, means to rotate the plate in timed relation with the feed screw and means including a pair of adjustable stops on said plate arranged to positively disconnect said clutch when the wheel slide has reached a predetermined position in either direction.

6. A feed mechanism for a grinding machine wheel slide, comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, manual means to rotate said feed screw, a power mechanism, means to connect said mechanism to rotate the feed screw, and means including an adjustable stop to disengage the power mechanism when the wheel slide has reached a predetermined position.

7. A feeding mechanism for a grinding machine wheel slide, comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, manual means to rotate said feed screw, a power mechanism, means including a manually operable lever and a clutch to connect said mechanism to rotate the feed screw in either direction and means including an index plate and a pair of adjustable stops to disengage the power mechanism when the wheel slide has reached a predetermined position.

8. A feed mechanism for a grinding machine wheel slide comprising a feed screw, a. nut engaging said screw and operatively connected to the wheel slide, a power mechanism, manually operated means to connect said mechanism to rotate the feed screw and move the slide rca-rwardly and a stopping mechanism including a member connected to move in timed relation with the feed screw arranged to disconnect the power mechanism when the wheel slide has reached a predetermined rearward position irrespective of the distance it has been fed toward the work.

9. A feed mechanism for a grinding machine wheel slide comprising a feed screw, a nutengaging said screw and operatively connected to the wheel slide, a power mechanism, means including a clutch to connect said mechanism to rotate the feed screw, means including a stop arranged to positively disconnect the clutch when the grinding wheel has been fed to a predetermined position close to the work, manual means to rotate the feed screw to give the wheel slide a further feeding movement to grind the work to the desired size and means to pre- Vent connecting the clutch during the manual feeding of the wheel.

10. A feeding mechanism for a grinding machine wheel slide comprising a rotatable feed screw, a nut engaging said screw and operatively connected to the wheel slide, a power mechanism, means including a manually opera le lever to connect said mechanism to rotate the feed screw and means operating upon the release by the operator of said lever to automatically disconnect said power mechanism and thereby stop the rotation of the feed screw.

-11. A feeding mechanism for a grinding machine wheel slide comprising a rotatable feed screw, a nut engaging said screw and operatively connected to a wheel slide, manual means to rotate said screw, a power mechanism, a gear and clutch mechanism arranged to connect said power mechanism to rotate the feed screw in either direction, a manually operable lever connected to operate said clutch and'a yieldable mechanism arranged to throw said clutch into a neutral position upon the release of the lever by the operator.

12. A feeding mechanism for a grinding machine wheel slide comprising a rotatable feed screw, a'nut engaging said screw and operatively connected to the wheel slide, a

power mechanism, a clutch arranged to connect said power mechanism to rotate the feed screw in either direction, means including a manually operable lever arranged to connect said clutch, and means including a pair of opposed springs arranged to throw said clutch to a neutral position when the operator releases his grasp upon said lever.

13. A feeding mechanism for a grinding machine wheel slide comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, a manually operable feed wheel, a clutch arranged to connect said wheel to rotate said feed screw, a power mechanism, means including a manually operable lever to connect said mechanism to rotate the feed screw in either direction and connections between said lever and clutch so arranged that when the power mechanism is in engagement, the clutch controlling the manual feed is disconnected.

14. A feeding mechanism for a grinding machine wheel slide comprising a feed screw, a nut engaging said screw and operatively connected to the wheel slide, a manually operable feed wheel, means including a clutch arranged to connect said wheel to rotate the feed screw, a power mechanism, means including a second clutch arranged to connect said power mechanism to rotate the feed screw in either direction, a manually operable lever arranged to control the movement of said second clutch and connections between the lever and said clutches so arranged that when the second clutch is in engagement to rotate the feed screw by power, the clutch controlling the manual ieed wheel is disconnected.

15. A feed mechanism for grinding ma chine wheel slides comprising a feed screw, a gear train adapted to rotate said screw, a power mechanism, a hand wheel, means including a clutch mechanism for connecting either the power intake or hand wheel to said gear train to rotate the same, and automatic means for positively disconnecting the power after the wheel has moved in either direction to predetermined positions.

Signed at Worcester, Mass, this 24th day of July, 1928.

GEORGE E. SMITH. 

